LP:604923 - RQG: UPDATEs report different affected_rows with non-default myisam-block-size

In MariaDB 5.2 (and not in 5.3 or MySQL), the last UPDATE from the sequence below returns a different number of affected_rows if executed with a non-default myisam-block-size.

To reproduce:

1. Record a .result file using the default myisam-block-size.

perl mysql-test-run.pl --no-check-testcases --record t/affected_rows.test

2. Run the test using a non-default value

perl mysql-test-run.pl -no-check-testcases --mysqld=-myisam-block-size=8K t/affected_rows.test

you will get something along those lines:

CURRENT_TEST: main.affected_rows
— /home/philips/bzr/5.2/mysql-test/r/affected_rows.result 2010-07-13 01:13:40.180143078 -0700
+++ /home/philips/bzr/5.2/mysql-test/r/affected_rows.reject 2010-07-13 01:14:04.053070435 -0700
@@ -554,4 +554,4 @@
...
-affected rows: 1
+affected rows: 0

mysqltest: Result content mismatch